HowTo display a virtual column inside a GridField unescaped?

Hallo,
I have a DataObject with a virtual column (getPathsAsString()). The return value of this does contain HTML code. When this column is displayed in a GridField, the HTML code will be escaped. Does anyone know how to make the GridField not to escape that column?

I've already tried to set a casting to HTMLText for that field. But that doesn't make any difference.